ul {
  width: 100%;
  overflow-x: auto;
  list-style-type: none;
  display: flex;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 1000;
  background-color: #fff;
  li {
    position: relative;
    text-decoration: none;
    margin: 0 5px;
    padding: 5px 0;
    white-space: nowrap;
  }
  .active {
    color: red;
    &::after {
      content: "";
      height: 2px;
      width: 100%;
      background-color: red;
      position: absolute;
      top: 90%;
      left: 0;
    }
  }

}
